A conventional bicycle crank includes a hole in one end for being connected with a pedal and the other hole in the other end of the crank so as to be connected to an axle of bottom bracket. The hole for being connected to the axle includes ridges and grooves in an inner periphery thereof and each of two ends of the axle has ridges and grooves on an outer periphery thereof so that the axle is co-rotated with the rotation of the crank. Nevertheless, there are gaps between the ridges of the crank and the axle so that the ridges of the crank impact ridges of the axle when the rider starts to rotate the crank. This not only produces noise during operation, but also accelerates wearing between the ridges. The larger the gaps are, the sooner that the crank disengages from the axle.
The present invention intends to provide a connection for the cranks to the axle wherein at least one positioning assembly is used to improves the connection between the axle and the crank.